/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jclouds.fallbacks;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Throwables.propagate;
import static com.google.common.util.concurrent.Futures.immediateFuture;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.NANOSECONDS;
import javax.inject.Inject;
import org.jclouds.date.DateCodec;
import org.jclouds.date.DateCodecFactory;
import org.jclouds.http.HttpResponse;
import org.jclouds.http.HttpResponseException;
import org.jclouds.rest.RetryAfterException;
import com.google.common.annotations.Beta;
import com.google.common.base.Optional;
import com.google.common.base.Ticker;
import com.google.common.net.HttpHeaders;
import com.google.common.util.concurrent.ListenableFuture;
/**
* propagates as {@link RetryAfterException} if a Throwable is an
* {@link HttpResponseException} with a {@link HttpResponse set} and a valid
* {@link HttpHeaders#RETRY_AFTER} header set.
*
* @see <a href="https://tools.ietf.org/html/rfc2616#section-14.37">Retry-After
* format</a>
*/
@Beta
public final class HeaderToRetryAfterException implements PropagateIfRetryAfter {
private final Ticker ticker;
private final DateCodec dateCodec;
/**
*
* @param ticker
* how to read current time
* @param dateParser
* how to parse the {@link HttpHeaders#RETRY_AFTER} header, if it
* is a Date.
* @return
*/
public static HeaderToRetryAfterException create(Ticker ticker, DateCodec dateCodec) {
return new HeaderToRetryAfterException(ticker, dateCodec);
}
/**
* uses {@link Ticker#systemTicker()} and {@link DateCodecFactory#rfc822()}
*/
@Inject
private HeaderToRetryAfterException(DateCodecFactory factory) {
this(Ticker.systemTicker(), factory.rfc822());
}
private HeaderToRetryAfterException(Ticker ticker, DateCodec dateCodec) {
this.ticker = checkNotNull(ticker, "ticker");
this.dateCodec = checkNotNull(dateCodec, "dateCodec");
}
@Override
public ListenableFuture<Object> create(Throwable t) {
if (!(t instanceof HttpResponseException))
throw propagate(t);
HttpResponse response = HttpResponseException.class.cast(t).getResponse();
if (response == null)
return immediateFuture(null);
// https://tools.ietf.org/html/rfc2616#section-14.37
String retryAfter = response.getFirstHeaderOrNull(HttpHeaders.RETRY_AFTER);
if (retryAfter != null) {
Optional<RetryAfterException> retryException = tryCreateRetryAfterException(t, retryAfter);
if (retryException.isPresent())
throw retryException.get();
}
return immediateFuture(null);
}
/**
* returns a {@link RetryAfterException} if parameter {@code retryAfter}
* corresponds to known formats.
*
* @see <a
* href="https://tools.ietf.org/html/rfc2616#section-14.37">Retry-After
* format</a>
*/
public Optional<RetryAfterException> tryCreateRetryAfterException(Throwable in, String retryAfter) {
checkNotNull(in, "throwable");
checkNotNull(retryAfter, "retryAfter");
if (retryAfter.matches("^[0-9]+$"))
return Optional.of(new RetryAfterException(in, Integer.parseInt(retryAfter)));
try {
long retryTimeMillis = dateCodec.toDate(retryAfter).getTime();
long currentTimeMillis = NANOSECONDS.toMillis(ticker.read());
return Optional.of(new RetryAfterException(in, (int) MILLISECONDS.toSeconds(retryTimeMillis
- currentTimeMillis)));
} catch (IllegalArgumentException e) {
// ignored
}
return Optional.absent();
}
}